Bull. nat. Hist. Mus. Lond. (Zool.) 60(1): 1-37 



Issued 23 June 1994 



THE NATUR AL 

 HISTORY MUSEU 



15 JUL 1994 

 hicoENTtD 



A new subfamily and genus in Achatinidae 

 (Pulmonata: Sigmurethra) 



ZOOLOGY LIB RA 



ALBERT R. MEAD 



Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA 



CONTENTS 



Synopsis 1 



Introduction 1 



Methods 3 



Abbreviations - Anatomical 3 



Achatinidae 3 



Key to subfamilies 3 



Callistoplepinae - new subfamily 3 



Key to genera 4 



Genus Callistoplepa 5 



Key to species 5 



Genus Leptocala 12 



Key to species 13 



Achatininae 18 



Genus Bequaertina - new genus 18 



Key to species 22 



Radulae and j aws 32 



Acknowledgements 35 



Acronyms 35 



Re f e rences 36 



Synopsis. In the Achatinidae, characteristics of the internal anatomy, particularly those in the reproductive tract, 

 are continuing to show greater dependability in determining phylogenetic affinities than those in the shell, radula or 

 jaw. In 1934, J.C. Bequaert reached the conclusion in the course of his revising the African land snail family 

 Achatinidae, 'that several of the East African Achatinae are not separable from the West Africa Callistoplepae, at 

 any rate as far as shell characters go'. The present 5-year study of over 500 shell specimens and 50 soft anatomies, 

 involving 11 genus-group and 57 species-group nomina, demonstrates that the 4 anatomically distinct West African 

 species, to which Bequaert referred, are the most primitive in the family. Accordingly, they have been placed in a 

 separate subfamily. Anatomically the 5 contrastingly different East African species were found to be a distinct 

 genus, plesiomorphic to subgenus Achatina [sensu Bequaert, 1950). Their phylogenetic relationships show a strong 

 correlation with the distributional evidence in 60 recorded localities, which delineates (1) a short north central axis, 

 (2) a central to eastern Africa axis, and (3) a strong north-south axis extending from eastern Africa into southern 

 Africa. This evidence supports the emerging pattern of terrestrial gastropod distribution in Africa. The present 

 project forms the foundation for a revision of the family, currently in progress. 



INTRODUCTION 



Fifty-seven species-group nomina associated with the acha- 

 tinid genus Callistoplepa have provided the basis for the 

 present 5-year project. The examination of over 500 shell 

 specimens and 50 soft anatomies has revealed the fact that 

 four West African anatomically distinct but related Lower 

 Guinea species, in two genera, constitute a separate, primi- 

 tive subfamily of the Achatinidae. Anatomical and concho- 

 logical studies place the five other valid species in a new 

 genus that is distributed in Central, Eastern and Southern 

 Africa. 



Taxonomy in the Achatinidae is based both on the shell 

 and on the soft anatomy, particularly that of the basal 

 reproductive tract. The shell is a permanent record that 

 reflects ontogenetically the influence of the environment, 

 whereas the soft anatomy reflects phylogenetically the influ- 

 ence of evolution. The latter, in the short term, is relatively 

 free of substantive changes, being limited to temporary 

 variations that reflect nutritional, developmental or repro- 

 ductive influence. For example, both immature and seriously 

 malnourished mature specimens have misleadingly attenu- 

 ated, thin reproductive tracts with greatly limited muscula- 

 ture; but the malnourished specimen can be readily 

 distinguished because it has a much larger reproductive tract 



) The Natural History Museum, 1994 



